The inventive concepts disclosed herein generally relate to the field of digitizers, including but not limited to optical pulse energy digitizers for direct sampling receivers. In optical electronics, photo-detected optical pulse energy is converted to a voltage signal through conversion circuits such as transimpedance amplifiers (TIAs). This type of conversion is used in applications, such as, high speed, high resolution analog-to-digital converters (ADCs), free space optical communications, coherent optical communications and the like. According to some applications, military radio frequency (RF) systems include wide bandwidth, high speed, high resolution ADCs that operate in, for example, wideband staring signals intelligence (SIGINT) receivers, flexible software defined radio (SDR) system architectures, and low probability of intercept/low probability of detection (LPI/LPD) radars. These systems often use electronic ADC (eADC) components.
U.S. Pat. No. 9,329,453, dated May 3, 2016, entitled OPTICAL PULSE ENERGY DIGITIZER, incorporated herein by reference in its entirety, discloses an analog front end of an optical pulse digitizer or ADC. In a conversion process, pulses generated by a photodiode are converted from current pulses into voltage pulses prior to quantization. As data rates increase, the frequency of the pulses increases accordingly and measuring the peak energy associated with each pulse when the frequency approaches or exceeds a certain level (e.g., 1 gigahertz (GHz) is more difficult.